Page 417 of 516

Black plate (51,1)Chevrolet Volt Owner Manual - 2011
Vehicle Care 10-51
(B) Tire Width:The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio
:A two‐digit
number that indicates the tire
height‐to‐width measurements.
For example, if the tire size
aspect ratio is 60, as shown in
item C of the illustration, it would
mean that the tire's sidewall is
60 percent as high as it is wide.
(D) Construction Code
:A
letter code is used to indicate
the type of ply construction in
the tire. The letter R means
radial ply construction; the
letter D means diagonal or
bias ply construction; and the
letter B means belted‐bias ply
construction.
(E) Rim Diameter
:Diameter of
the wheel in inches. (F) Service Description
:These
characters represent the load
index and speed rating of the
tire. The load index represents
the load carrying capacity a tire
is certified to carry. The speed
rating is the maximum speed a
tire is certified to carry a load.
Tire Terminology and
Definitions
Air Pressure:The amount
of air inside the tire pressing
outward on each square
inch of the tire. Air pressure is
expressed in kPa (kilopascal)
or psi (pounds per square inch).
Accessory Weight
:The
combined weight of optional
accessories. Some examples
of optional accessories are,
automatic electric drive unit,
power steering, power brakes,
power windows, power seats,
and air conditioning. Aspect Ratio
:The relationship
of a tire's height to its width.
Belt
:A rubber coated layer of
cords that is located between
the plies and the tread. Cords
may be made from steel or other
reinforcing materials.
Bead
:The tire bead contains
steel wires wrapped by steel
cords that hold the tire onto
the rim.
Bias Ply Tire
:A pneumatic
tire in which the plies are laid
at alternate angles less than
90 degrees to the centerline
of the tread.
Cold Tire Pressure
:The
amount of air pressure in a tire,
measured in kPa (kilopascal)
or psi (pounds per square inch)
before a tire has built up heat
from driving. See Tire Pressure
on page 10‑54.
Page 418 of 516

Black plate (52,1)Chevrolet Volt Owner Manual - 2011
10-52 Vehicle Care
Curb Weight:The weight of a
motor vehicle with standard and
optional equipment including the
maximum capacity of fuel, oil,
and coolant, but without
passengers and cargo.
DOT Markings
:A code
molded into the sidewall of
a tire signifying that the tire
is in compliance with the U.S.
Department of Transportation
(DOT) Motor Vehicle Safety
Standards. The DOT code
includes the Tire Identification
Number (TIN), an alphanumeric
designator which can also
identify the tire manufacturer,
production plant, brand, and
date of production.
GVWR
:Gross Vehicle Weight
Rating. See Vehicle Load Limits
on page 9‑14. GAWR FRT
:Gross Axle
Weight Rating for the front axle.
See Vehicle Load Limits on
page 9‑14.
GAWR RR
:Gross Axle
Weight Rating for the rear axle.
See Vehicle Load Limits on
page 9‑14.
Intended Outboard Sidewall
:
The side of an asymmetrical tire,
that must always face outward
when mounted on a vehicle.
Kilopascal (kPa)
:The metric
unit for air pressure.
Light Truck (LT‐Metric) Tire
:A
tire used on light duty trucks and
some multipurpose passenger
vehicles.
Load Index
:An assigned
number ranging from 1 to 279
that corresponds to the load
carrying capacity of a tire. Maximum Inflation Pressure
:
The maximum air pressure to
which a cold tire can be inflated.
The maximum air pressure is
molded onto the sidewall.
Maximum Load Rating
:
The load rating for a tire at the
maximum permissible inflation
pressure for that tire.
Maximum Loaded Vehicle
Weight
:The sum of curb
weight, accessory weight,
vehicle capacity weight, and
production options weight.
Normal Occupant Weight
:
The number of occupants a
vehicle is designed to seat
multiplied by 68 kg (150 lbs).
See Vehicle Load Limits on
page 9‑14.
Occupant Distribution
:
Designated seating positions.
Page 420 of 516

Black plate (54,1)Chevrolet Volt Owner Manual - 2011
10-54 Vehicle Care
Vehicle Capacity Weight:
The number of designated
seating positions multiplied by
68 kg (150 lbs) plus the rated
cargo load. SeeVehicle Load
Limits on page 9‑14.
Vehicle Maximum Load on the
Tire
:Load on an individual tire
due to curb weight, accessory
weight, occupant weight, and
cargo weight.
Vehicle Placard
:A label
permanently attached to a
vehicle showing the vehicle's
capacity weight and the
original equipment tire size
and recommended inflation
pressure. See “Tire and Loading
Information Label” underVehicle
Load Limits on page 9‑14.
Tire Pressure
Tires need the correct amount
of air pressure to operate
effectively.
Notice: Neither tire
underinflation nor
overinflation is good.
Underinflated tires, or
tires that do not have
enough air, can result in:
.Tire overloading and
overheating which could
lead to a blowout.
.Premature or
irregular wear.
.Poor handling.
.Reduced fuel economy. Overinflated tires, or tires
that have too much air, can
result in:
.Unusual wear.
.Poor handling.
.Rough ride.
.Needless damage from
road hazards.
The Tire and Loading
Information label on the
vehicle indicates the original
equipment tires and the correct
cold tire inflation pressures.
The recommended pressure
is the minimum air pressure
needed to support the vehicle's
maximum load carrying capacity.
Page 433 of 516

Black plate (67,1)Chevrolet Volt Owner Manual - 2011
Vehicle Care 10-67
Temperature–A, B, C
The temperature grades
are A (the highest), B, and C,
representing the tire's resistance
to the generation of heat and
its ability to dissipate heat
when tested under controlled
conditions on a specified indoor
laboratory test wheel. Sustained
high temperature can cause
the material of the tire to
degenerate and reduce tire life,
and excessive temperature
can lead to sudden tire failure.
The grade C corresponds to a
level of performance which all
passenger car tires must meet
under the Federal Motor Safety
Standard No. 109. Grades B
and A represent higher levels of
performance on the laboratory
test wheel than the minimum
required by law. Warning: The temperature grade for this tire
is established for a tire that
is properly inflated and not
overloaded. Excessive speed,
underinflation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.
Wheel Alignment and Tire
Balance
The tires and wheels were
aligned and balanced at the
factory to provide the longest tire
life and best overall performance.
Adjustments to wheel alignment and
tire balancing will not be necessary
on a regular basis. However, check
the alignment if there is unusual tire
wear or the vehicle is pulling to one
side or the other. If the vehicle is
vibrating when driving on a smooth
road, the tires and wheels may need
to be rebalanced. See your dealer
for proper diagnosis.
Wheel Replacement
Replace any wheel that is bent,
cracked, or badly rusted or
corroded. If wheel nuts keep coming
loose, the wheel, wheel bolts and
wheel nuts should be replaced.
If the wheel leaks air, replace it.
Some aluminum wheels can be
repaired. See your dealer if any
of these conditions exist.
Your dealer will know the kind of
wheel that is needed.
Each new wheel should have
the same load-carrying capacity,
diameter, width, offset and be
mounted the same way as the
one it replaces.
Page 453 of 516

Black plate (87,1)Chevrolet Volt Owner Manual - 2011
Vehicle Care 10-87
Recreational Vehicle
Towing
Recreational vehicle towing refers to
towing the vehicle behind another
vehicle such as a motor home.
The two most common types of
recreational vehicle towing are
known as dinghy towing and dolly
towing. Dinghy towing is towing the
vehicle with all four wheels on the
ground. Dolly towing is towing the
vehicle with two wheels on the
ground and two wheels up on
a device known as a dolly.Here are some important things to
consider before recreational vehicle
towing:.The towing capacity of the
towing vehicle. Read the
tow vehicle manufacturer's
recommendations.
.How far the vehicle can be
towed. Some vehicles have
restrictions on how far and
how long they can tow.
.Does the vehicle have the
proper towing equipment.
See your dealer or trailering
professional for additional
advice and equipment
recommendations.
.Is the vehicle ready to be towed.
Just as preparing the vehicle
for a long trip, make sure the
vehicle is prepared to be towed.
Dinghy Towing
Notice:
If the vehicle is towed
with all four wheels on the
ground, the drive unit could be
damaged. Repairs would not be
covered by the vehicle warranty.
Do not tow the vehicle with all
four wheels on the ground.
The vehicle was not designed to
be towed with all four wheels on
the ground. If the vehicle must
be towed, a dolly should be used.
See “Dolly Towing” that follows for
more information.